Saku City in Nagano holds a hot air balloon festival for 3 days every Golden Week. It's neat! There are races between the balloons. Also, there is the chance for spectators to ride in a balloon.
Here is a Japanese link to the Saku Balloon Festival.
I got up early to travel the few miles to the venue. I could have just stayed home and let the balloons come to me!
At night, there was a pyrotechnic display. I stayed away from the crowds and watched it from Kokuzoyama, a viewpoint above the Healthy Terrace Michi no Eki.
Have a great Golden Week!